Contour map of the predicted altitude above the Earth's surface where the electron density reaches its maximum value constructed by Solar Terrestrial Dispatch

(updated every 30 minutes)

The Basic Facts:

The global contour map gives the height maximum of the F2 layer (abbreviated hmF2) in kilometers above the Earth's surface. Also shown are the current location of the auroral oval, the locaton of the sunrise/sunset terminator and the regions where the sun is less than 12 degrees below the horizon (called the gray-line corridor). In the gray-line corridor, the lowest altitude ions are rapidly lost as the sun sets but the high altitude ions are still plentiful. These are particularly good conditions for short-wave radio signal propagation. The higher the altitude of the F2 peak, the farther the radio signal will be able to propagate.